Latest Seasonal Assessment -
Hot, dry weather intensified drought across much of the
Great Plains during the first 3 weeks of August, with the Kansas-Missouri area recording triple
digit heat from August 16-20, and scattered locations from Texas to Minnesota reporting
negligible rainfall for the month to date. Some of the dryness has been very persistent. As
of August 20, there had been no measurable rain in Lubbock, Texas since June 26. The
seasonal outlook through November calls for drought to essentially persist from the Dakotas
into Kansas and Missouri, although cooler weather and scattered bouts of rain will bring
occasional relief to the region. The odds for relief are better in the southern Plains, as the
outlook calls for improvement from southern Kansas into Texas. However, the confidence in
the drought outlook is low for the Plains states, as there are no strong indications of above
or below normal rainfall during September-November. In the West, summer thunderstorms
have brought scattered relief as expected, and even flooding, but high temperatures have
offset some of the rain's beneficial impacts. Continued scattered improvement is expected
from the Southwest region into the northern Rockies, although pronounced relief from the
water shortages will depend on the upcoming winter snow season. Less chance for drought
relief is expected over the Great Basin and in much of Montana and eastern Idaho. In the
Pacific Northwest, seasonal rains, especially during October-November, should ease the
agricultural drought affecting the region. Seasonal rains are also expected to provide modest
improvement for the drought affecting Hawaii.

Discussion for the Seasonal Drought Outlook

Tools used in the drought outlook included: the official CPC long-lead
for the next 90 days, the Palmer Drought Index probability projections for the next 3 months, and various medium
and short-range forecasts and models such as the 6-10 day and 8-14 day forecasts and the
2-week soil moisture forecast. Additional tools included the constructed analogue from soil moisture forecasts.

With weak signals from the various forecast tools regarding the Sep-Nov
outlook for precipitation over most of the country, this forecast focuses on
climatology, the constructed analogue soil moisture tool for November, and the
near-term circulation trends as seen in the latest model runs.

The soil moisture analogue tool -CAS--implies a tendency for drought to
persist in the South Dakota-Nebraska-northern Kansas area, and the short to
medium-range forecasts have been showing only light rain in this area, so the
odds favor persisting drought. The confidence is lower for the Missouri-
southern Iowa area, as the CAS suggests improvement. But some of the
statistical and dynamical tools used for the 90-day precipitation forecasts
show a tendency for below-normal rainfall from the Great Lakes into Oklahoma,
and available 10-day and 15-day soil moisture forecasts show drying in this
area, so the odds favored persisting drought here as well. For the
Minnesota-Wisconsin area, confidence is very low due to ambiguous or
conflicting signals, but some indications of a pattern of ridging to the west
and troughing to the east, and a resulting tilt toward below-normal rainfall,
led to the forecast of persisting. There is also a seasonal tendency for
rainfall to diminish as we go into November.

The area with limited improvement in the West is based on the CAS for November
and medium range outlooks. Widespread thunderstorms are on tap for parts of
the West in the next 1 to 2 weeks. More significant improvement is unlikely
until we are well into the winter snow season. CAS and climatology suggest
less improvement for much of Montana into the Great Basin. Climatology
indicates improvement for Washington and Oregon, as precipitation is generally
substantial by the end of November, especially in western areas. The
improvement for Hawaii is also based on expected increased seasonal rainfall.